With a little work, this could be a really nice tuba. Merlin Grady has one of these same tubas (with the string linkages, Dan!) for $3,500. I have no idea what repair work the eBay tuba needs or how much it would cost... but for $2,900 + some repair work, I think you could still end up with a very good deal.

I would argue that these are not "huge," but they are in that large 4/4 to small 5/4 size category. PLENTY of sound.